Help: Tyre Scrubbing

[Nismo_286]

I fitted 17x8" wheels in the front of my R32 GTST. However, the tyres keep scrubbing onto my front strut arms (or is it the steering arm?). Thus inducing some tyre noises everytime i turn at tight corners and brake hard.

Are the wheels offset wrong? I read that an offset of +38 is used for the stock wheels. And my aftermarket wheels are having an offset of +45. Kindly advice.

Also, because this wheels are just 2 months old, do I have the right to complain to the tyre shop. Afterall, they were the ones who mentioned that fitting the mentioned sizes would be of no consequences.

Last but not least, if i stiffen the springs, would it reduce the tyres scrubbing?

Thanks guys for your input.

[nissky]

I fitted 17x8" wheels in the front of my R32 GTST. However, the tyres keep scrubbing onto my front strut arms (or is it the steering arm?). Thus inducing some tyre noises everytime i turn at tight corners and brake hard.

Are the wheels offset wrong? I read that an offset of +38 is used for the stock wheels. And my aftermarket wheels are having an offset of +45.  Kindly advice.

Also, because this wheels are just 2 months old, do I have the right to complain to the tyre shop. Afterall, they were the ones who mentioned that fitting the mentioned sizes would be of no consequences.

Last but not least, if i stiffen the springs, would it reduce the tyres scrubbing?

Thanks guys for your input.

hmmm thats wierd i had 17x8inch with +38 offset at front with 235's and they didnt rub...but different brand tyres can have have slightly different widths...

but yeh it was tight maybe 3mm gap between upper arm and inside of tyre

why are you braking hard while turning tight corners ;p (brake before the corner :headspin: :headspin: )

[Demon Dave]

AFAIK, in most cases the offset of the wheels should be the same as, or less than factory. I can't remember what the offset for the 33's is, but for the R34 it's +40. Most aftermarket wheels recommend offsets of +30 to + 40, depending on the width and design of the wheel...

It does sound to me like the + 45 offset at the front is a little too much...

[nissky]

a positive offset pushes the tyres further out, so if its rubbing on the inside the offset should be larger...

or have i got this mixed up?

[Richelieu]

By increasing the offset you have most probably increased the scrub radius.

Any bump or cornering force applied to the tyre exerts a twisting force on the steering that is proportional to the scrub radius. If the scrub radius were zero the twisting forces would be zero. By increasing the scrub radius you have increased the force exerted on your tyres hence greater scrub.

Stiffer springs will not solve this. You need to get rims with the correct offset.

[Demon Dave]

a positive offset pushes the tyres further out, so if its rubbing on the inside the offset should be larger...

or have i got this mixed up?

tis the other way around. The greater the positive offset, the more the wheels are "pulled" towards the centre of the car.

at 0 offset, the hub is aligned exactly with the centre line of the wheels width (i.e. 4inches on a 8inch wide rim)

Positive offsets bring the hub closer to the outer face of the wheel, thus the inner edge is effectively pulled inwards. The reverse is true of negative offsets.

To see if a set of wheels will fit I often use this online utility:

Wheel Offset Calculator

Regards

Dave

[nissky]

ah yes...brain fade

more positive offset pushes centre hub outwards which pulls rim in...

[Nismo_286]

Thanks nissky.

R your offsets the same for the fronts and backs?

What is the size of your rear wheels?

I am having +45 offset on the rears, but they r not rubbing against anything. Do you think that I should change them to a +38 or +35 offset?

Thank you so much.

[Duncan]

Thanks Demon Dave, excellent link

[Roy]

I dont think my rims are ideal, but...

I only have +25 on the front of my 17 x7 rims (to help clear the brakes), with rears being +30 and 17 x 8

Car's ride height is 315mm on the front and 340mm at the rear, measured from centre of rim to lip on guard. With 215/45/17s on front and 245/45/17s on the rear i dont have any trouble with rubbing.

When i have 235/45/17s on the front they rub on the guard a little bit/ocassionally, but definitely have a healthy clearance to all susp/brake components.

[Demon Dave]

I've been debating what wheels to get for my R34 for over a year now (kinda fills in the time saving up the money too ) As a result I've been on just about every manufacturers site checking for compatible wheel sizes/offsets. As a general rule of thumb, for the R34 GTT's (and I'm guessing the 33 GTSt's) you want offsets of around:

+30 to +38 ish at the front

+35 to + 40 at the rear.

The lower offset at the front is to ensure the rims clear the inner suspension, strut, lower arm etc.

The higher offsets at rear are just to push out the rear wheels a little more. Clearance on the inside of the wheel isn't really much of an issue.

But really, the ideal offset depends on:

the size, particularly the width and style of the wheel (deep dish etc)

Your choice of tyres

How much the car is lowered

How much rubbing/scrubbing your prepared to live with!

If you're having problems with the wheels you have now, you might want to consider using some spacers? They'll decrease the offset, pushing the wheel away from the centre line of the car (i.e. sticking out of the fenders more) and help reduce scrubbing on the inner edges...

[VIPERGTSR01]

yeah seems like you are in need of spacers. Or sell the rims

[Nismo_286]

Thanks to all of you for your input...

FYI, I have gone back to the shop that sold me the rims - the staff has promised to change my fronts to a +35 from a +45 offset.

[Demon Dave]

Thanks to all of you for your input...

FYI, I have gone back to the shop that sold me the rims - the staff has promised to change my fronts to a +35 from a +45 offset.

Good result. That offset should solve the rubbing problem you have, though it *may* cause the tyres to rub slightly against the inner black plastic guard at full lock. Don't worry though, no damage will be caused to either the tyre or the plastic guard. I had the same thing happen with my 33 and I ran the same wheels/tyres for 2 years without any adverse effects...